Composition and method for preserving wood



UNll'l'ED sTA'rEs PATENT, OFFICE COMPOSITION AND METHOD FOR I I PBESEBVING WOOD Enoch Bertram, Bnflalo, N. Y.,

Preserving Wood too-none museum Ina.

Buhalo, Pl. Y., a corporation of New York 8 Claims. (01. 167-48.?)

The present invention relates to'the preservation of'wood and particularly to a process and a composition for the preservation of wood. This application is a continuation-in-part ofmy copending United States application Serial Number 181,106, filed December 22, 1937.

.It is known to coat moist wood with an aqueous paste comprising a water-soluble wood preservative thickened with a. water-swelling gum and permitting the preservative to diffuse into the wood by osmosis. However, such aqueous pastes dry out quickly, show little adhesion to the wood and are readily washed oifthe wood when exposed to rain. Therefore, it is a general object of the present invention to provide a composition for preserving moisture-containing wood which will not dry out rapidly, show strong ad hesion to the wood surface, and which will be resistant to removal by rain.

It is a specific object of the invention to provide a bi-functional wood preserving composition containing at least one organic water-insoluble preservative and at least one water-soluble preservative, the latter being present in such Physical form that it will difluse slowly into the either an organic and/or inorganic preservative agent such as the mycocide salts and insecticides.

In general, suitable inorganic salts are those which are soluble in water and comprise materials such as the soluble fluorides of sodium, po-

tassium and ammonium, zinc chloride, copper wood by osmosis but will be substantially resistant to leaching by exposure to rain;

It is also a specific object to provide a simple and eflicient method of preserving wood with such bi-functional compositions.

The invention comprises in general, without the use of iorced impregnation, a process of preserving wood containing moisture by applysulphate, mercuric chloride, as well as soluble arsenates, chromates, bichromates and the like. including chromated zinc chloride and zinc silico-iiuoride. In lieu of, or in addition to, the water-soluble inorganic preservative, there may also be employed in the composition organic wood preservatives which are only partially soluble in water as, for instance, dinitrophenol, dinitrocresol, trinitrophenol and the like.

For certain types of-application, the carrier may be mixed with diluents or thinners and to this end relatively inert materials such as petroleum distillates or light oils are found suitable although where the preservative composition is to be used for certain treatments, creosotes and light tar fractions in general are excellent diluents. v

Fillers that aid in its spreading power upon application and retain the preservative in the carrier may also be added to the composition. The fillers that have been found satisfactory include the colloidal clays, the well known bentonite clays, diatomaceous 'earth and materials of 30 like physical characteristics. The amount of filler added may comprise any amount consistent with the production of a composition readily aping to the debarked surface of the wood a viscous,-

tacky, non-aqueous composition comprising a water-insoluble organic ,wood preservative carrying in suspension a water-soluble wood preservative, permitting said water-soluble preservative to dilfuse into the wood by osmosis through the medium of the moisture contained in said wood. the water-insoluble organic 'carrier anchoring the water-soluble inorganic preservative to the surface of the wood and forming a toxic surface coating.

The composition of the present invention contains essentially a water-soluble wood preservative and a water-insoluble organic carrier therefor that is toxic, viscous and tacky. The waterinsoluble carrier of the present invention comprises normally solid or semi-solid, organic wood preservatives such as asphalt or mineral pitch,

tar or resinous pitch, as well as bitumen and related products, such as coal tar, all of these products being generally designated as pitch.

The water-soluble wood preservative may be to plied in use without eliminating the tacky character of the composition and rendering the same friable, granular and noncoherent.

Where the water-insoluble carrier is normally solid, as is the case with some mineral pitches, the carrier is heated to melt the same and the water-soluble wood preservative incorporated in the molten pitch, generally by stirring. Since.

the water-soluble wood preservatives are in general insoluble in the pitch,.the former will exist as solid particles in suspension in the pitch.

The various ingredients of the composition are intimately mixed together and the resultant mixture then applied to a surface of the moist wood to be treated, which wood should be free of bark. If the wood does not contain suflicient moisture, it should first be soaked in or sprayed with water befo e being treated with the composition. S anding poles, posts, piles and timbers that have been in use and that have absorbed moisture may be treated with the composition of the presc-nt invention by applying the same to the wooden member or those portions where preservative acof checks and cracks in logs, timbers and lumj ber where the same is-green or water laden, and, v

in fact, may be used for the, impregnation ofall forms of timber which drilled or,

cut when such wood contains moisture.

ance with the invention, the green wood is stripped of bark in'any convenient fashion in order to expose a wood surface free of bark, the

debarked surface is coated with the viscous, tarry material'comprising a carrier of pitch and a water-soluble'preservative for the wood, and the so-coated wood permitted to stand until the water-soluble preservative has penetrated the wood. The carrier penetrates the surface to a slight degree, but" being" water-insoluble, the major part remains on the surface forming a oughly incorporated therein by stirring until a suspension is formed.

'As an example of such a compound, the following ingredients may be employed:

1 After cutting away the rotted parts of the standing pole, the preservative composition is applied to that portion of the pole subject to ground line action. The asphalt and oil form a substantially water-impervious layer about the 1e and u n hardenin of the as halt a co- In the preservation of green timber in accordp0 Do 8 p herent coating is formed carrying in it the prerelatively hard, dense pitehy coatingwhich ex=-.

cludes insects and prevents entrance of moisture into the wood with attendant rotting and leaching of the water-soluble preservative. The quantity of preservative applied to the wood may vary in accordance with the nature'and size of the tree, as well as in accordance impregnation desired. 7

Where 'it is desiredto impregnatethe wood only'with a mycocide salt,a composition comprising the following ingredients may be employed, this composition being merely illustrative of'the invention rather than limitative thereof. One gallon of the material may comprise approximately the following composition:

Pounds Semi-fluid pi c 8 Sodium fluoride I v 5 Bentonite clay Y 2 The completed composition is made by heating the pitch,.ifthe same be solid, to obtain a liquid pitch and then mixing the solid sodium fluoride with the depthhof servative materials. -Where conditions warrant, a waterproof bandage may be wrapped about the coated portion of the pole to insure additional protection to the preservative composition.

Another preservative composition that has been found satisfactory in use upon standing poles is one having per gallon the following ingredients:

. Pounds Fluid coal tar (viscosity 7-9 Engler) 6 to 8 Sodium fluoride 6 to! Sodium bichromate V to 1 Dinitrophenol Veto V For application of the composition to thewood to be preserved, the composition, where solid, is melted and the fluid, molten material applied to the wood surface to be treated as, for instance,

v applied by spraying.

Upon application of the composition of the present invention to wood, the pitch serves to anchor the water-soluble preservative tothe surface even when rain beats on the wood. The

; moisture'in the wood permitsthe diffusion of the water-soluble preservative by osmotic pressure since tests upon treated wood show that the preservative gradually reaches the interior of the wood with' excellent penetration in preservative and bentonite uniformly throughout the molten mass. If the pitch be'semi-liquid or liquid, the

preservative agents maybe directly admixed. After admixture the mass stiflens and sets and may be shipped for use in drums.

Where timbers are to be and treat I ed with a mycocide salt as well as an insecticide, thetimbers are treated at the portion to be preserved with a composition per gallonas folconcentration after a few months. The carrier remains substantially on the surface and by reason of its toxicity prevents rotting of the surface layers.

'Ihe'preservative composition is effective as a preservative in eliminating further decay at the ground line of standing poles, such as telephone 1ows,"the water-insoluble carrier being mineral pitch, the insecticide being 'di'nitrophenol and potassium bichromate, the mycocidesalt being sodium fluoride:

p I Pounds Solid bitumen 2 Creosote oil 5 Sodium fluoride 5 Potassium bichromate 1 Dinitroph nnl ,4,

The creosote oil and solid bitumen are heated and stirred until the mass contains no lumps of undissolved bitumen. watersoluble preservatives are added and thor- To this mass the solid poles, power line poles, piling, fenceposts and the 1ike,.by scraping away the decayed or rotted portions ofthe standing pole andapplying the composition of the present invention comprising a wood preservative and a water immiscible carriertherefor. In treatment of standing poles, it may be advantageous to select mycocides and insecticides that react within the wood to produce diflicultly soluble materials having the general structure ofa cryolite compound. For example, there may be used a water-soluble inorganic dichromate with a water-soluble fluoride or arsenate.

- By the present invention there is provided a novel composition for the preservation of wood whether the same be green wood, felled timber or timber'in construction such as standing poles.

The mode of preserving the wood is advantageous in that expensive equipment is not necessary and manual labor has been reduced over processes presently suggested.

As changes may be made in the composition embodied in the present invention without departing from its scope, it is intended that the above composition shall be deemed illustrative and not limitative.

I claim:

1. A process for preserving green or waterladen wood without the use of forced impregnation, comprising applying to the debarked surface of wood containing moisture a viscous, tacky, non-aqueous composition comprising a water-insoluble organic wood preservative as a vehicle carrying in suspension a substantial proportion of solid particles of a stable, water-soluble mycocide preservative which is insoluble in the vehicle, permitting said water-soluble preservative to diffuse into the wood by osmosis through the medium of the moisture contained in the wood, the water-insoluble carrier forming a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

2. A process for preserving green or waterladen wood without the use of forced impregnation, comprising applying to the debarked surface of wood containing moisture a viscous, tacky, non-aqueous composition, comprising a waterinsoluble organic wood preservative as a vehicle carrying in suspension a substantial proportion of solid particles of a stable, water-soluble inorganic mycocide preservative which is insoluble in the vehicle, permitting said'water-soluble preservative to difiuse into the wood by osmosis through the medium of the moisture contained in the wood, the water-insoluble carrier forming a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

3. A process for preserving green or waterladen wood without the use of forced impregnation, comprising applying to the debarked surface of wood containing moisture a viscous, tacky, non-aqueous composition, comprising a waterinsoluble organic wood preservative consisting of normally solid pitch and a liquid organic diluent as a vehicle carrying in suspension a substantial proportion of solid particles of a stable watersoluble mycocide preservative which is insoluble in the vehicle, permitting said water-soluble preservative to diffuse into the wood by osmosis through the medium of the moisture contained in the wood, the water-insoluble carrier forming a water-impervious zone at the surface of the treated wood to prevent the leaching-out of the water-soluble preservative. w

4. A wood-preserving composition applicable to green or water-laden wood comprising a viscous, tacky, non-aqueous composition, comprising a water-insoluble organic wood preservative as a vehicle carrying in suspension a substantial proportion of solid particles of a stable watersoluble mycocide wood preservative which is insoluble in the vehicle, said water-soluble preservative being adapted to diffuse into moistureladen wood by osmosis and the water-insoluble carrier being adapted to form a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

5. A wood-preserving composition applicable to green or water-laden wood comprising a viscous, tacky, non-aqueous composition, comprising a water-insoluble organic wood preservative as a vehicle carrying in suspension a substantial proportion of solid particles of a stable watersoluble inorganic mycocide wood preservative which is insoluble in the vehicle, said watersoluble preservative being adapted to diffuse into moisture-laden wood by osmosis and the water-insoluble carrier being adapted to form a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

6. A wood-preserving composition applicable to green or water-laden wood comprising a viscous,

tacky, non-aqueous composition, comprising a water-insoluble organic wood preservative consisting of normally solid pitch and a liquid organic diluent as a vehicle carrying in suspension a substantial proportion of solid particles of a stable water-soluble inorganic mycocide wood preservative which is insoluble in the vehicle, said water-soluble preservative being adapted to diffuse into moisture-laden wood by osmosis and the water-insoluble carrier being adapted to form a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

7. A wood-preserving composition applicable to green or water-laden wood comprising a viscous, tacky, non-aqueous composition, comprising pitch and creosote oil as a vehicle and carrying in suspension a substantial proportion of solid particles of a stable water-soluble mycocide wood preservative which is insoluble in the vehicle, said water-soluble preservative being adapted to diffuse into moisture-laden wood by osmosis and the water-insoluble carrier being adapted to form a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

8. A wood-preserving composition applicable to green or water-laden wood comprising a viscous,

tacky, non-aqueous composition, comprising coal tar as a vehicle and carrying in suspension 2. substantial proportion of solid particles of a stable water-soluble mycocide wood preservative which is insoluble in the vehicle, said water-soluble preservative being adapted to diflfuse into moistureladen wood by osmosis and the water-insoluble carrier being adapted to form a water-impervious zone at the surface of the treated wood to prevent the leaching out of the water-soluble preservative.

ENOCH BQS'I'RUM. 

